The $182 billion-asset bank based in Winston-Salem, N.C., said Wednesday it had endured a so-called denial of service attack a day earlier that left some customers unable to access their accounts.

The bank "definitely experienced some DDoS activity," BB&T spokesman Brian Davis told American Banker, referring to a dedicated denial of service attack. "It was an afternoon event," said Davis, who added that the website functioned normally again by evening.

The assault is at least the third on BB&T since September and comes amid a wave of electronic onslaughts that have slowed websites at some of the nation's biggest banks.

At least some of the attacks have tapped protocols and harnessed cloud computing facilities to exploit vulnerabilities in banks' cyber defenses, according to experts.

Though a group that calls itself the al Qassam Cyber Fighters says it is waging the attacks in retaliation for an American-made, anti-Muslim film trailer that remains posted on YouTube, some U.S. officials have tied the incursions to the Iranian government, which has denied responsibility.

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